Adoption records are confidential, and each individual state has control over access to the records. States close adoption records to the general public, and those requesting access must get court approval or have mutual consent from all involved in the adoption process.
A closed adoption shares no information between the adoptive parents and the birth parents. It is extremely hard, if not impossible, for adopted children to gain access to closed adoption records. Permission from a judge would be necessary to unseal these records.
An open adoption allows for contact between the adoptive parents and birth parents. The parties involved can choose whether the records will be made available to the child when he or she reaches adult age, and what information will be available. An adopted child can hire an attorney or go to the local courthouse for information about obtaining adoption records in his or her state.